Armstrong furnace 8 flashes: Rollout switch open
Eight flashes means a rollout switch opened. Flame came forward out of the burner compartment instead of being drawn into the heat exchanger. This is the most serious code on the control.
Applies to: Whichever of Armstrong Air, AirEase, Concord, or Ducane is on the nameplate, the furnace is an Allied Air Enterprises A80UH1E or 80G1UHE with the -02 integrated control, and this code reads the same.
What it means
Rollout switches sit on or near the burner assembly and open when they detect heat where there should be none. They exist to catch flame rollout — flame escaping forward out of the burner box rather than being pulled through the heat exchanger by the draft. Rollout means the combustion path is obstructed or the draft has failed. It can scorch wiring, damage the furnace, and produce carbon monoxide. Unlike the limit switches, which reset themselves once things cool, a rollout switch is manual reset: it stays tripped until someone physically presses it. That is deliberate, so that a person has to attend the furnace and establish why before it runs again.
Most common causes
- A blocked or restricted heat exchanger, so combustion gases cannot pass through it.
- A blocked or partly blocked flue, forcing combustion products back toward the burners.
- A failed or weak draft inducer not pulling flame into the heat exchanger.
- A cracked heat exchanger disturbing the combustion airflow.
- Burners that are dirty, misaligned or partly blocked.
- Insufficient combustion air in a confined furnace space.
- Overfiring, with gas pressure set too high for the burners.
How to diagnose it
- Treat this as a stop-and-call fault rather than something to work through. Its causes are dominated by conditions that produce carbon monoxide.
- Check that carbon monoxide alarms are present and working. If any has sounded, leave and call the fire service from outside.
- Look for visible scorching, soot or melted wire insulation near the burner compartment — from outside, without dismantling anything.
- Note whether the flue or vent termination is obviously blocked.
- Note that this control gives rollout its own code, so eight flashes is unambiguous — it is not sharing a count with anything less serious.
How to fix it
- Turn the furnace off at its service switch and call a licensed heating technician.
- Do not press the rollout switch reset button to restart the furnace. It tripped because flame went somewhere it should not, and resetting without finding out why puts the furnace straight back into that condition.
- Have working carbon monoxide alarms on every level of the home and outside each sleeping area, which is what NFPA and CPSC guidance call for.
- Every underlying cause — heat exchanger, flue, inducer, burners, gas pressure — is licensed work. There is no homeowner portion of this repair.
Notes
The manual reset on a rollout switch is the clearest signal a furnace gives about how seriously to take a fault. Every other common safety resets itself; this one requires a person, precisely so the condition gets investigated rather than cycled through.
Related
- 7 flashes — Primary or secondary limit open, or Watchguard after three minutes open
- 12 flashes — Flame sensed without the gas valve energised
All codes for this manufacturer
Armstrong Air, AirEase, Concord and Ducane furnace codes — every code, with what differs between models.
Not sure this is your brand?
The same count means something else on other furnaces. What 8 flashes means on every brand puts them side by side.
What the fix costs
Price this one by its cause, not its switch. The switch itself sits in the $150–350 band the furnace repair cost guide lists for limit-family parts — but a rollout switch that tripped almost certainly did its job, and what tripped it is the real bill: an obstructed combustion path, failed draft, or burner trouble. The worst finding, a compromised heat exchanger, runs $1,000–2,500+ and is usually the point where the replacement cost math beats the repair. On this code specifically, be more suspicious of a cheap quote than an expensive one — cheap usually means nobody found the cause.
Do it yourself or call someone?
Call. This is the least DIY code on the control. The switch is manual-reset precisely so that a person has to attend the furnace and establish why flame escaped the burner box before it runs again — pressing the button and walking away defeats that safeguard. No filter check applies here: flame left the place it belongs, the cause is in the combustion path, and finding it needs instruments. Working CO alarms on every level, including the furnace's, are part of the fix rather than an accessory to it.
The same trip on other control families
Rollout gets its own code on most brands: Goodman's 6 flashes, the 5 red on the GMEC96-family board (which also covers a blown control fuse), and Lennox's hard-lockout alert 200. Carrier is the outlier — it folds rollout into the shared limit-circuit code 33, so a Carrier owner cannot separate the two from the code alone, where eight flashes here is unambiguous. Cross-brand list: rollout switch codes.
What this looks like
From the outside, a tripped rollout switch usually looks much like the furnace heats then trips out on high limit, except this one needs a manual reset before the furnace will run again — that walkthrough covers what to check in order.